document.write( "Question 550468: PROVE: An angle bisector of the vertex angle of an isosceles triangle is also an altitude. Thanks. \n" ); document.write( "
Algebra.Com's Answer #358807 by Edwin McCravy(20056)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "Given: ᐃABC, \r\n" );
document.write( "       AB ≅ AC, \r\n" );
document.write( "       AD bisects ∠BAC \r\n" );
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document.write( "To prove: AD ⊥ BC \r\n" );
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document.write( " Steps:                       Reasons:\r\n" );
document.write( "1.   AB ≅ AC                  Why?\r\n" );
document.write( "2. ∠ABD ≅ ∠ACD               Why?\r\n" );
document.write( "3.   AD ≅ AD                  Why?\r\n" );
document.write( "4. ᐃABD ≅ ᐃADC               Why?\r\n" );
document.write( "5. ∠ADB ≅ ∠ACD               Why? \r\n" );
document.write( "6.  m∠ADB = m∠ACD = 90°      Two congruent angles that form a linear \r\n" );
document.write( "                              pair are right angles\r\n" );
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document.write( "7.   AD ⊥ AC                  Why?              \r\n" );
document.write( "8.   AD is an altitude        Why?\r\n" );
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document.write( "I filled in the reason for step 6.  You fill in the reasons for the\r\n" );
document.write( "other steps.  You could combine two of the steps.\r\n" );
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document.write( "Edwin

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